Mentor

A mentor is "someone who teaches or gives help and advice to a less experienced and often younger person," in a story, the experienced guide who trains or counsels the protagonist. The word descends from Mentor, son of Alcimus, in Homer's Odyssey, and the origin is instructive: the poem's Mentor is "a somewhat ineffective old man," and it is Athena assuming his appearance who guides the young Telemachus, so the guidance, not the man, makes the mentor. The senior party serves "as an advisor, counsellor, or guide"; the recipient may be a protégé, protégée or apprentice.

For the novelist the mentor is a story function, not a personality: in Vogler's eight archetypes it is one of the roles defined relative to the hero, and its mythic face is the wise old man. Keep it distinct from the confidant, who listens; the mentor speaks first.